The Squad S02 E02 Episode 2

Elena investigates her father's death and, rummaging through his belongings, finds an anonymous letter in which the son of a convict accused the judge of having killed his father, Gennaro Barreto, innocently in prison. The woman finds Nicola Barreto and kills him. The police investigate her murder and Pietro Guerra discovers that her culprit is her partner Elena di lei: Pietro will therefore find himself arresting her.